Numerous procedures are currently performed or are under consideration for both therapeutic and cosmetic (both aesthetic and reconstructive) purposes in which a temporary or permanent substance is injected or otherwise implanted into or through the skin layers to targeted cutaneous, subcutaneous and intramuscular tissue regions. By way of example, procedures that implant collagen-emitting fibroblasts, hyaluronic acid products and/or muscle inhibitors (e.g., Botox®) for facial or body rejuvenation or reconstruction involve making a number of injections of minute amounts of substances into targeted intradermal and subcutaneous tissues (e.g., between the epidermis and the dermis; within the dermis, or into the subcutaneous fat and intramuscular layers). Another example is the injection of fat cells into a subcutaneous fat layer for facial or body “lipo-contouring”.
Such procedures are often labor intensive, and require a number of skin-piercing, i.e., “transcutaneous” injections, with each injection delivering a relatively small quantity of a substance to a given depth below the skin surface, and in a given pattern, into the targeted tissue. The intradermal injection of pigments (e.g., for tattoos) is another example of a well-known, labor intensive process in which pigment ink is repeatedly injected into the dermis to form a desired (and stable) pattern that is visible through the epidermis. By way of yet another example, it has been proposed to inject stem cells to grow hair, e.g., hair follicular cells or inductive dermal papilla cells, into the areas of the scalp in which the patient's natural hair follicular cells are no longer growing.
One well-known transcutaneous procedure is hair transplantation, which typically involves (in the case of male pattern baldness) harvesting donor hair follicles (or grafts containing multiple follicles) from the side and back fringe areas of the patient's scalp, and implanting the hair follicles or grafts in a bald “recipient” area on the top and top-front of the scalp. “Follicular units” are naturally occurring aggregates of 1-3 (and much less commonly, 4-5) closely spaced hair follicles that are distributed randomly over the surface of the scalp. Until recently, both the harvesting and implantation of follicular units has been performed manually, and can be a very laborious and painstaking procedure.
Automated (e.g. robotic) systems and methods for harvesting and implanting hair follicular units have been invented and are currently under commercial development by Restoration Robotics, Inc., of Mountain View, Calif. (assignee of the present application). In particular, U.S. Pat. No. 6,585,746 to Gildenberg[, which is incorporated herein by reference in its entirety,] discloses a hair transplantation system utilizing a robotic system, including a robotic arm and a hair follicle introducer associated with the robotic arm. A video system is used to produce a three-dimensional virtual image of the patient's scalp, which is used to plan the scalp locations that are to receive hair grafts implanted by the follicle introducer under the control of the robotic arm.
U.S. patent application Ser. Nos. 11/380,903, filed Apr. 28, 2006, and 11,421,438, filed May 31, 2006 (collectively “Bodduluri”), which are incorporated herein by reference in their entirety, disclose and describe an automated system for transplanting hair follicular units, which employs a multi-part tool assembly carried on a distal end of a robotic arm. The tool assembly is independently controllable relative to the robotic arm, and includes an inner, “harvesting” cannula with a longitudinal axis that is automatically aligned (under image-guidance) with a selected follicular unit to be harvested from a donor area of a body surface, and then advanced relative to the body surface so that an open, tissue coring distal end of the harvesting cannula penetrates the body surface surrounding the selected follicular unit to a depth sufficient to substantially encapsulate the follicular unit. The harvesting cannula is then withdrawn from the body surface with the follicular unit engaged by and retained in an interior lumen thereof. An outer, “implanting” cannula is disposed coaxially over (and moveable relative to) the harvesting cannula, wherein a tissue piercing distal end of the implanting cannula is used to puncture a recipient area of the body surface and form an implantation cavity, with the follicular unit displaced from the harvesting cannula lumen into the implantation cavity.
While these advances with regard to hair transplantation are very promising for reducing if not eliminating the need for such procedures to be performed manually, there remains a need for similar automated apparatus for performing other procedures involving the transcutaneous delivery of therapeutic and cosmetic substances to cutaneous, subcutaneous and intramuscular tissue regions, especially procedures that require a precise location of a large number of sub-dermal injections.